MONDAY, Aug. 31 (HealthDay News) -- The complicated medical history of John F. Kennedy still exerts a pull on medical sleuths nearly 50 years after the former president's death.

A new report by a U.S. Navy physician claims that Kennedy suffered from a more complex endocrine problem than the Addison's disease he was diagnosed with as a young man.

In the Sept. 1 issue of Annals of Internal Medicine, Dr. Lee Mandel, senior medical officer aboard the aircraft carrier U.S.S. George H.W. Bush, writes that Kennedy suffered from autoimmune polyendocrine syndrome type 2 (APS-2), a rare disorder that can lead to Addison's disease, hypothyroidism and other glandular diseases.

Mandel based his findings on the voluminous medical records now open to the public at the John F. Kennedy Presidential Library & Museum in Boston.

"Kennedy had more medical issues than most of us were aware of," said Mandel, a specialist in internal medicine and an amateur historian. "But he got the job done despite all of those conditions. I admire the man."

Kennedy's first bout with adrenal disease was in the 1940s. On a trip to England in 1947, Kennedy, then a congressman from Massachusetts, collapsed. A physician diagnosed Addison's, an adrenal gland defect, and told Kennedy's friends that he had less than a year to live. Kennedy returned to the United States, where he began treatment with first-generation steroids.

Addison's disease occurs when the adrenal glands do not produce enough hormones, especially cortisol, which has many major functions, among them maintaining blood pressure, cardiovascular function and healthy levels of glucose in the blood. Symptoms of Addison's include fatigue, extreme weakness and substantial weight loss, all of which Kennedy experienced before he started therapy.

Kennedy's doctor's also believed that he had hypothyroidism, or insufficient thyroid hormone. Symptoms of hypothyroidism include depression, a puffy face and joint and muscle pain.

"There's a common thread to all of these conditions," deduced Mandel. "All I did was pick up the clues that were out there anyway."

According to Mandel, the thread was APS 2, also known as Schmidt syndrome. APS 2 is an autoimmune disorder, sometimes running in families, in which the body is unable to produce several essential hormones. Many APS 2 patients have problems with their sex glands, pancreas and digestive system. The American Academy of Family Physicians estimates that APS 2 affects five out of every 100,000 people in the United States.

Mandel found another set of clues in two of Kennedy's relatives. According to Mandel, Kennedy's younger sister, Eunice Kennedy Shriver, who recently died at the age of 88, had Addison's disease. His son, John Jr., had Graves' disease, another autoimmune condition.

"Approximately one half of patients with APS 2 have relatives with autoimmune diseases," added Mandel.

Since APS 2 was not described until 1980, Kennedy's physicians may not have suspected a unifying disease connecting his endocrine problems. Furthermore, treatment for APS 2 is the same as for Addison's. So, the new diagnosis does not mean that Kennedy was necessarily sicker than his physicians knew or less able to carry out his presidential duties, said Mandel.

"It just means that now we may have a better understanding of his health problems," Mandel said. "Remarkably, John F. Kennedy managed to convey an image of health and vigor."

Dr. Paul Margulies, medical director of the National Adrenal Diseases Foundation and a practicing endocrinologist from Manhasset, N.Y., agreed with Mandel's findings and recalled how careful Kennedy's doctors were to keep the president's true condition from the public.

JFK enjoyed a level of privacy (many would say secrecy) unknown to politicians today. By contrast, Senator Ted Kennedy, the president's youngest brother who was buried Aug. 29, fought brain cancer in a very public way, beginning with the announcement of his diagnosis in May 2008.

The president's endocrinologist and most important physician was Dr. Eugene Cohen, who kept JFK's secret for years after his assassination in 1963. "I knew Gene Cohen in the 1970s," said Margulies. "Even then he was very circumspect."